Process for making pile-surfaced material



Patented June 15, 1954 UNITED STATES ATEN T OFFICE PROCESS FOR MAKINGPILE-SURFACED MATERIAL Spondon, ecutor and Trustee Derby, and .lolinlate of Spondon, Jane Blackmore,.

England, joint executors, assignors, by mesne assignments,,to (lelaneseCorporation of America, a corporation of Delaware No Drawing.Application November Serial N 255,310

Claims priority, application Great Britain November 7, 1950 Thisapplication is a continuation-in-part of application Serial No. 91,092,filed May 3, 1949.

This invention relates to textile fabrics and other materials andespecially to pilesurfaced materials containing cellulose acetatein thepile and/or in the-backing;

It is known to make pile fabrics by: bonding short textile fibres to asuitable backing, for example a textile fabric, the fibres being pr0-jected on to the adhesive-coated fabric, for example by blowing or bythe action of an electrical field, and the adhesive being subsequentlyconverted from the sticky condition to a. non sticky flexible condition.An important object of the present. invention is to make pile fabrics ofthis kind containing cellulose acetate in the pile. and/Orrin: thebacking, the said: fabrics to have a soft: handle; to: be waterresistant and capable OfTIBSiStii'lg. moderately elevated temperatures,forexampleup t,o*100. C.,,and being capable of dry cleaningwithoutdamage.

Flor making pilefabrics of the kind. referredto. containing cellulose.acetate, great difiiculty was: experienced :in. devising: apsuitableadhesive composition. One quality most necessary in the adhesiveaiscthatit should beobtainable in a very sticky condition.v Unfortunately the:adhesives in. which this: characteristic ;is. most. marked. are; forthe: most: part. highly water-sensitive even in the hardened condition.Adhesivesshowing considerable stickiness, can be formulated from. rubbereither inasolutionlor in the form of-latex'. but-rubber showsnospecificadhesive properties towards cellulose acetate. and

oanised. Polychloroprene shows the same disadvantages with lessstickiness. before hardening. Polyvinyl acetate can 1 be used: in.solution or in dispersion, e. guin a plasticiseror evenin water, to;formulate: adhesives which are-sufficiently sticky and whichcan 'behardened-to give a .flexw moreoveris not-reg sistant to dry cleaningsolvents even whenyultion as polyvinyl acetate and which needs specialplasticisers, e. g. cyclohexyl phthalate, to give strong adhesion tocellulose acetate. The desired: degree of stickiness is still' moredifficult to ob tain with polymerised esters of acrylic acid andmethacrylic acid. These fective in resistance to polymers also arededry-cleaning solvents.

.As is well known, the resistance to solvents of copolymers is usuallyrelatively low, and various copolymers tried, including copolymers ofvinyl acetate with vinyl chloride, provedunsuitable.

We have now found, however, that a suitable adhesive can be formulatedfrom a rubber-like copolymer of butadiene with acrylonitrile that.

contains at least 20 0 by weightof combined acrylonitrile, for example,the. polymers sold under the registered trade-marks Hycar O. R. 25".and.

ethyl ketone in admixture with methyl isobutyl. ketone or diethylketone, which does not damage.

the cellulose acetate. Products obtained by the use of this adhesivehave shown an excellentsofti handle.

According, therefore, to. the process of the invention, pile surfacedmaterials are mad by impelling fibres on to an adhesive-coated web andhardening the adhesive, the fibre and/or the. web having a basis ofcellulose acetate, the adhesive containing a rubber-like copolymer ofbutadiene and acrylonitrile which is vulcanised during the hardeningstep. The invention includes pile surfaced materials the pile isanchored to the backing by a vulcanised rubber-like copolymer ofbutadiene and acrylonitrilecontainingat least 20% of combinedacrylonitrile.

It is of advantage for the acrylonitrile content e: g. 25-

Moreover,

in which pile and/ r or backing are of cellulose acetate. and inwhichcopolymer containing to with one containing to 4.5% ofacrylonitrile, can be used. It is also possible to use blends of thecopolymer, especially a copolymer containing 40 to of acrylonitrile,with a minor proportion of polyvinyl chloride.

Preferably the adhesive composition contains in addition to the polymerand the vulcanising ingredients at least one plasticiser for thesynthetic rubber of low volatility, for example dibutyl phthalate orbetter still a higher phthalate, for instance di-Z-ethyl-hexylphthalate, or dicyclohexyl phthalate or tricresyl phosphate. In additionit is of advantage to have present a more volatile plasticiser of highsolvent power for cellulose acetate, for example dimethyl phthalate,and, as in the process of our British Patent No. 644,002, thisplasticiser may be to a large extent removed by volatilisation in thecourse of vulcanisation. To facilitate the evaporation of the morevolatile plasticiser without undue loss of the less volatile one, themore volatile plasticiser should have at least 5 times, and preferably10 to times, the vapour pressure at 150 C. of the less volatileplasticiser and its vapour pressure at that temperature should not beless than 5 mm. The copolymer may be plasticised by a suitable polymericplasticiser, e. g. a polyester such as poly-1.2-propylene glycolsebacate. It is also of advantage to have present an anti-oxidant, forexample beta-phenyl naphthylamine, with a view to maintaining the stability of the polymer.

The following are examples of suitable adhesives according to theinvention, all parts being by weight:

Example I 150 parts of Hycar O. R. 25

3 parts of sulphur 3 parts of a 4:1 mixture of mercaptobenzthiazole anddiphenyl guanidine 7.5 parts of zinc oxide 37.5 parts of a cumaroneresin of M. P. 130 C.

300 parts of dimethyl phthalate 45 parts of di-2-ethyl-hexyl phthalate3'78 parts of methyl ethyl ketone 252 parts of methyl isobutyl ketone 3parts of pigment Example I I 800 parts of Hycar 0. R. 15

1600 parts of dimethyl phthalate 400 parts of di-2-ethyl-hexyl phthalate80 parts of a resin of softening point 123 C.

obtained by polymerisation of a petroleum cracking distillate in whichnone of the unsaturated constituents boils below 130 C., at least of thetotal weight of the unsaturated constituents consists of one or both ofthe substances beta-methyl styrene and indene, and said total weightdoes not contain as much as 5% of any di-unsaturated substance 90 partsof zinc oxide 16 parts of sulphur 8- parts of stearic acid 2 parts oftetramet'nyl thiuram disulphide 8 parts of benzthiazyl disulphide 24parts of yellow ochre 2560 parts of a 60:40 mixture (by volume) ofmethyl ethyl ketone and methyl isobutyl ketone Example III Thecomposition is as in Example II except with reference to the that thedi-2-ethyl-hexyl phthalate is replaced by di-cyclo-hexyl phthalate.

In making the compositions of these examples the synthetic rubber ismilled e. g. for 7 minutes at 20 to 30 C. with the nip of the rolls setat 0.015 inch, and is then soaked in the mixture of ketones for at least48 hours, after which it is mixed for about 30 minutes in a Werner-Pfieiderer, then the plasticisers are added and mixing continued for afurther 2 hours. Finally, not more than 24 hours before use, thecompounding ingredients are mixed in, the accelerators last.

With cellulose acetate fibre, excellent results have been obtained usingas the backing-fabric a fabric of cotton or other form of cellulose,including regenerated cellulose. Fabrics of high tenacity regeneratedcellulose such as is obtainable by saponifying cellulose acetate yarnthat has been stretched considerably in steam or hot water areparticularly suitable when a strong lightweight backing fabric isrequired. Backin fabrics of other materials can be used, includingmaterials of higher dielectric constant and dielectric strength andlower moisture regain than cotton, for example silk, wool, casein,soya-bean protein and other proteinaceous fibres; cellulose acetate;fibre-forming condensation polymers such as nylon; fibre-formingaddition polymers such as copolymers of vinyl chloride with vinylacetate, with vinylidene chloride, or with acrylonitrile, or ofacrylonitrile with methacrylonitrile; and mineral fibre-formingmaterials such as glass. Instead o1 using a fabric for the backingmaterial, other flexible non-metallic webs can be used, e. g. webs ofpaper or films of regenerated cellulose or of a cellulose ester or ether(e. g. the acetate, propionate, acetate-propionate or acetate-butyrate,or ethyl cellulose) or of any of the synthetic polymers referred toabove. Metal fabrics or foils can also be used.

With a backing web made of or containing cellulose acetate the staplefibre used may be composed of any of the materials specified abovebacking fabric. Excellent products have been obtained with staple fibreof length between 0.5 and 5 mm, and especially between 05 and 2 mm. andof denier 2.5 to 5. The fibre should be free from oil and substantiallydry.

The invention includes the use of cellulose acetate fibres in admixturewith other fibres, and the use as the backing of mixed fabrics, e. g.fabrics containing yarns of cellulose acetate in admixture with yarns ofany other of the fibreforming materials referred to above. The backingfabric may be composed of continuous filament yarns; or of staple-fibreyarns; or of a mixture of the two. When the backing fabric is composedwholly or for the most part of a fibreforming material to which theadhesive does not stick as readily as it does to cellulose acetate, itis of advantage to employ that material in the form of a staple fibreyarn or at least to have picks or warps of such yarn atintervals in thefabric. Similarly with such a material it is of advantage to interweavecellulose acetate yarns at intervals.

The best results have been obtained with a cellulose acetate fibre and abacking of a cellulose acetate woven fabric, e. g. a jappe, taffeta,poplin or satin fabric. A novel purpose to which pile fabrics made fromsuch a combination can be put is in making eiderdowns and like coverletshaving a. reduced tendency to slip.

Products particularly useful fortrimmings, e. g. iirmillinery, andproducts useful as furnishing fabrics, carrbemade by bonding celluloseacetat'e fibre to a film-or foil of cellulose acetate. Owing tc'thepoorspecificadhesive properties of cellulose-acetate towards mostadhesives, the manufacture of such materials has hitherto presentedseriousdifficulty; It will, of course, be understood that materialshaving a backing of film or foil will-not possessthe soft handlereferred to aboveas one of the advantages obtainable by thepresentinvention when using fabric back ingsa I The pile surfacedmaterials of the inventionare preferably made by a continuous processinwhich the web which is to form the backing, in the course of itstravel past a number of successive stations, receives a coating ofadhesivein sticky condition or as a solution or dispersion which is madesticky by evaporation before the fibreapplylng station is reached; hasprojected onto this' coatin'g the fibre requiredto form the: pile; isicarried through a region in which the adhesive is hardened byvulcanisation of the copolymer and evaporation of any substantialremaining quantities of volatile substances; andkis collected withoutdamaging the pile. The projection of the fibre on to the fabric may bedone by means of anair blast or under the impulsion of a constant orvarying; electric field of high potential in which the fibres becomecharged. Vulcanisation is preferably effected by carrying thematerialtin festoonsthrough aheated chamber;

The following example illustrates theproduction of pile surfaced fabricaccording to the invention Example IV in which the volatile solvents areevaporated, and

then downwards through an electrostatic plate condenser the plates ofwhich are parallel to and extend across the whole width of the fabricand are inch apart, and thence horizontally again through a vulcanisingchamber. To the condenser is applied on alternating voltage of the orderof 10,000 volts at a frequency of the order of 10 cycles per secondthrough a transformer fed by an A. C. generator driven by a variablespeed D. C. motor. To avoid sparking in the condenser at least one ofits plates should be covered on the inside by a layer of insulatingmaterial, e. g. a sheet of polyvinyl chloride or polystyrene. Dry,oil-free cellulose acetate fibre of length 0.5 to 1 mm. and denier 2.5to 5 is fed into the space between the adhesive coated surface of thefabric and the adjacent condenser plate and the speed of the motordriving the generator is adjusted to give a frequency which causes thefibres to move to and fro between the coated surface and the adjacentelectrode while falling under gravity, until they become impaled on thesurface -or fall clear.

The vulcanising cabinet is kept at a temperature of 85 to 95 C. and thefabric runs through it in festoons in the course of to hours. In thisperiod the synthetic rubber is vulcanised and most of the dimethylphthalate is evaporated leaving the coating flexible and non-sticky.

6, Eitample v" The. process is, carried out, as described in Ex.- ampleIV'but substituting for the adhesive the composition. of Example III.

Having described our invention, what. we desire to secure. by. Letters.Patent. is:

1'..In a process for makingpile-surfacedimae basis of a synthetic rubberwhich is a copolymer of butadiene. with at. least 25% of its weight, ofacrylonitrile, saidl adhesive containing also vulcanizingflingredientsfor the synthetic rubber together with av plasticizer for celluloseacetate havingavapor pressure at C. of at least 5 mm. and a. plasticizerfor the synthetic rubber of vapor pressure ncgreater than onefifththatof: the. first-mentioned plasticizer, applying the fibre to thecoateclweb, carrying. the wehthrough a: heated zone and in said zonevulcanizing, the synthetic rubber and evaporating the: greater part of.the 7 more volatile plasticizer.

abasis of synthetic rubber Whichis acopolymer of butadiene with at least25%. of its weight of acrylonitrile, said adhesive containing. alsovulcanizing ingredients for the synthetic rubber phthalate.

3. In a process for making pile-surfaced material by causing loosecellulose acetate fibres to adhere to an adhesive-coated surface of atravelling web and hardening the adhesive, the steps of coating the webwith an adhesive having acrylonitrile, said adhesive containing alsovulcanizing ingredients for the synthetic rubber together with dimethylphthalate and di-2- ethyl-hexyl phthalate, applying the fibre to thecoated web, carrying the web through a heated 4. In a process for makingpile-surfaced material by causing loose cellulose acetate fibres toadhere to an adhesive-coated surface of a travelling web and hardeningthe part of the dimethyl phthalate.

5. In a process for making pile-surfaced material by causing loosecellulose acetate fibres to adhere to an adhesive-coated surface of atravelling web and hardening the adhesive, the steps of coating the webwith an adhesive having a basis of a synthetic rubber which is acopolymer of butadiene with at least 25% of its weight of acrylonitrile,said adhesive containing also vulcanizing ingredients for the syntheticrubber together with dimethyl phthalate, di-2- ethyl-hexyl phthalate anda cumarone resin, applying the fibre to the coated web, carrying the webthrough a heated zone, and in said zone vulcanizing the synthetic rubberand evaporating the greater part of the dimethyl phthalate.

6. In a process for making pile-surfaced material by causing loosecelluloseacetate fibres to adhere to an adhesive-coated surface of atravelling web and hardening the adhesive, the steps of coating the webwith an adhesive having a basis of a synthetic rubber which is acopolymer of butadiene with at least 25% of its weight of acrylonitrile,said adhesive containing also vulcanizing ingredients for the syntheticrubber together with dimethyl phthalate, di-2-ethylheXyl phthalate and aresinous copolymer of fl-methyl styrene and indene, applying the fibreto the coated web, carrying the web through a heated zone, and in saidzone vulcanizing the synthetic rubber and evaporating the greater partof the more volatile plasticizer.

7. In a process for making pile-surfaced material by causing loosecellulose acetate fibres to adhere to an adhesive-coated surface of atravelling web and hardening the adhesive, the steps of coating the webwith a solution in a mixture of methyl ethyl ketone and methyl isobutylketone of an adhesive having a basis of a synthetic rubber which is acopolymer of butadiene with at least 25% of its weight of acrylonitrile,said adhesive containing also vulcanizing ingredients for the syntheticrubber together with dimethyl phthalate, di-Z-ethylhexyl phthalate anda'cumarone' resin, evaporating off the methyl ethyl ketone and methylisobutyl ketone, applying the fibre to the coated web, carrying the webthrough a heated zone, and in said zone vulcanizing the synthetic rubberand evaporating the greater part of the dimethyl phthalate.

8. In a process for making pile-surfaced material by causing loosecellulose acetate fibres to adhere to an adhesive-coated surface of atravelling web and hardening the adhesive, the steps of coating the webwith a solution in a mixture of methyl ethyl ketone and methyl isobutylketone of an adhesive having a basis of a synthetic rubber which is acopolymer of butadiene with at least 25% of its weight of acrylonitrile,said adhesive containing also vulcanizing ingredients for the syntheticrubber together with dimethyl phthalate, di-2-ethylhexyl phthalate and aresinous copolymer of p-methyl styrene and indene, evaporating of: themethyl ethyl ketone and methyl isobutyl ketone, applying the fibre tothe coated web, carrying the web through a heated zone, and in said zonevulcanizing the synthetic rubber and evaporating the greater part of thedimethyl phthalate.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A PROCESS FOR MAKING PILE-SURFACEED MATERIAL BY CAUSING LOOSECELLULOSE ACETATE FIBERS TO ADHERE TO AN ADHESIVE-COATED SURFACE OF ATRAVELLING WEB AND HARDENING THE ADHESIVE, THE STEPS OF COATING THE WEBWITH AN ADHESIVE HAVING A BASIS OF A SYNTHETIC RUBBER WHICH IS ACOPOLYMER OF BUTADINE WITH AT LEAST 25% OF ITS WEIGHT OF ACRYLONITRILE,SAID ADHESIVE CONTAINING ALSO VULCANIZING INGREDIENTS FOR THE SYNTHETICRUBBER TOGETHER WITH A PLASTICIZER FOR CELLULOSE ACETATE HAVING A VAPORPRESSURE AT 150* C. OF AT LEAST 5 MM. AND A PLASTICIZER FOR THESYNTHETIC RUBBER OF VAPOR PRESSURE NO GREATER THAN ONE FIFTH THAT OF THEFIRST-MENTIONED PLASTIZER, APPLYING THE FIBER TO THE COATED WEB,CARRYING THE WEB THROUGH A HEATED ZONE AND IN SAID ZONE VULCANIZING THESYNTHETIC RUBBER AND EVAPORATING THE GREATER PART OF THE MOVE VOLATILEPLASTICIZER.